You did not explain what are you going to use port forwarding for. So, I'd venture to propose, additionally to using -L flag, setting up a SOCKS proxy for applications that support it (for example Firefox):

ssh -D *:9999 user@remote_host

Common use is to configure Firefox to use this SOCKS proxy, with network.proxy.socks_remote_dns turned on, to tunnel your HTTP session through other host.

main purpose was transparently forward connections from host1(old) on concrete port to host2(new) same port host1 contains server, that accept users connections, this server were moved and until dns database is updating need support also connections to old host this is the task
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duganetsJun 11 '09 at 9:16

thx, am i wrong when think you talk about one machine with serveral interfaces (ip's)? but i have to different freebsd host on two different ISP's and one possible connection between it only via internet
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duganetsJun 13 '09 at 9:43